Project: brine4power

“Green mega-battery for green energy”

EWE is developing the world’s largest battery as a green storage facility for green electricity using redox flow technology: b4p storage.

Redox flow batteries are liquid batteries. The Friedrich Schiller University in Jena has developed a new and pioneering metal-free redox flow battery based on a salt solution (brine). EWE will use this new development to operate salt caverns as electricity storage facilities.

Principle of operation

A redox flow battery consists of two storage containers and an electrochemical cell in which the reactions take place.

The two electrolytes – catholyte and anolyte – are separated from one another in the electrochemical cell by a membrane. This prevents the electrolytes from mixing. However, the ions are able to move unimpeded through the membrane from one electrolyte solution to the other.

When the battery is being charged, the charging current ensures that electrons are added to the polymers of the anolyte (REDuction). At the same time, the catholyte releases its electrons (OXidation).

The catholyte and anolyte molecules charged in this way are pumped from the cell into the storage container and replaced by uncharged molecules. The reaction is reversed when the battery discharges. The anolyte molecules release their electrons which are then available as electric current.

The maximum storage capacity of this redox flow battery is limited only by the size of the storage container for the electrolyte liquids.

Both charged electrolytes can then be stored for several months.

The world's largest battery

EWE is an expert in large storage facilities, operating salt caverns for secure gas storage and future secure electricity storage in salt domes under the low North German plain and in Brandenburg.

Two caverns, each with a volume of 100,000 m³, will be used for the world’s largest battery. They are flushed with water in salt domes, generating the required brine on site.

The project

Project phases
Project phases In order to realise this ambitious project, an expert team of partners from science and industry is researching and developing the world’s largest battery: b4p storage.

Phase

Facility

Planned operating figures

1

Test facility 1
(above ground)

10 - 20 kW
10 - 40 kWh

2

Test facility 2
(above ground)

100 - 500 kW
500 - 2,500 kWh

3

Pilot facility
(underground cavern)

up to 120 MW
up to 700 MWh

For comparison:
The electrical capacity of 700 MWh is sufficient to supply over 75,000 households with electricity for one day.

Image: optimised electrical storage cavern (new construction)

Battery of the future

Redox-flow battery based on brine and polymers:

Scalable

Cost efficient

Sustainable, non-flammable

Durable

Virtually no self-discharge

Added value in Europe

Electrical energy storage

Unique

Applications:

Control energy

Primary

Secondary

Minute

Energy trading

Black-start

b4p storage

The missing piece of the puzzle in a successful energy turnaround

The cost of a cavern battery per kilowatt corresponds roughly to that of pump storage power plants or conventional batteries. However, the ability to store large amounts of energy/MWh makes b4p storage unbeatably cost efficient. In future, renewable energy will be available at all times in sufficient quantities.

brine4power is the project for cost-effective, safe and sustainable power storage. In combination with a suitably sized wind farm, each battery replaces a controllable 120-megawatt power plant, supplying constant and clean energy at consistent prices.